 /*******************************************************************************
  * Copyright (c) 2000, 2003 IBM Corporation and others.
  * All rights reserved. This program and the accompanying materials
  * are made available under the terms of the Common Public License v1.0
  * which accompanies this distribution, and is available at
  * http://www.eclipse.org/legal/cpl-v10.html
  *
  * Contributors:
  * IBM Corporation - initial API and implementation
  *******************************************************************************/
 package org.eclipse.ui.internal.console;


 import org.eclipse.jface.text.BadLocationException;
 import org.eclipse.jface.text.DocumentEvent;
 import org.eclipse.jface.text.IDocument;
 import org.eclipse.jface.text.IDocumentListener;
 import org.eclipse.jface.text.ITypedRegion;
 import org.eclipse.jface.text.TextViewer;
 import org.eclipse.swt.SWT;
 import org.eclipse.swt.custom.LineStyleEvent;
 import org.eclipse.swt.custom.LineStyleListener;
 import org.eclipse.swt.custom.StyleRange;
 import org.eclipse.swt.custom.StyledText;
 import org.eclipse.swt.graphics.Color;
 import org.eclipse.swt.widgets.Composite;

 public class MessageConsoleViewer extends TextViewer implements LineStyleListener {
     
     protected InternalDocumentListener fInternalDocumentListener= new InternalDocumentListener();
         
     /**
      * Internal document listener.
      */
     class InternalDocumentListener implements IDocumentListener {
         /* (non-Javadoc)
          * @see org.eclipse.jface.text.IDocumentListener#documentAboutToBeChanged(org.eclipse.jface.text.DocumentEvent)
          */
         public void documentAboutToBeChanged(DocumentEvent e) {
         }
         
         /* (non-Javadoc)
          * @see org.eclipse.jface.text.IDocumentListener#documentChanged(org.eclipse.jface.text.DocumentEvent)
          */
         public void documentChanged(DocumentEvent e) {
             revealEndOfDocument();
         }
     }
     
     /**
      * Creates a new console viewer and adds verification checking
      * to only allow text modification if the text is being modified
      * in the editable portion of the underlying document.
      *
      * @see org.eclipse.swt.events.VerifyListener
      */
     public MessageConsoleViewer(Composite parent) {
         super(parent, getSWTStyles());
         getTextWidget().setDoubleClickEnabled(true);
         getTextWidget().setFont(parent.getFont());
         getTextWidget().addLineStyleListener(this);
         getTextWidget().setEditable(false);
     }
     
     /**
      * Returns the SWT style flags used when instantiating this viewer
      */
     private static int getSWTStyles() {
         int styles= SWT.H_SCROLL | SWT.V_SCROLL;
         return styles;
     }

     /**
      * Reveals (makes visible) the end of the current document
      */
     protected void revealEndOfDocument() {
         IDocument doc = getDocument();
         int lines = doc.getNumberOfLines();
         try {
             // lines are 0-based
 int lineStartOffset = doc.getLineOffset(lines - 1);
             StyledText widget= getTextWidget();
             if (lineStartOffset > 0) {
                 widget.setCaretOffset(lineStartOffset);
                 widget.showSelection();
             }
             int lineEndOffset = lineStartOffset + doc.getLineLength(lines - 1);
             if (lineEndOffset > 0) {
                 widget.setCaretOffset(lineEndOffset);
             }
         } catch (BadLocationException e) {
         }
     }

     /* (non-Javadoc)
      * @see org.eclipse.jface.text.ITextViewer#setDocument(org.eclipse.jface.text.IDocument)
      */
     public void setDocument(IDocument doc) {
         IDocument oldDoc= getDocument();
         IDocument document= doc;
         if (oldDoc == null && document == null) {
             return;
         }
         if (oldDoc != null) {
             oldDoc.removeDocumentListener(fInternalDocumentListener);
             if (oldDoc.equals(document)) {
                 document.addDocumentListener(fInternalDocumentListener);
                 return;
             }
         }

         super.setDocument(document);
         if (document != null) {
             revealEndOfDocument();
             document.addDocumentListener(fInternalDocumentListener);
         }
     }
     
     /* (non-Javadoc)
      * @see org.eclipse.jface.text.TextViewer#canPerformFind()
      */
     protected boolean canPerformFind() {
         return (getTextWidget() != null && getVisibleDocument() != null && getVisibleDocument().getLength() > 0);
     }
         
     /**
      * Dispose this viewer and resources
      */
     public void dispose() {
     }
     
     /* (non-Javadoc)
      * @see org.eclipse.swt.custom.LineStyleListener#lineGetStyle(org.eclipse.swt.custom.LineStyleEvent)
      */
     public void lineGetStyle(LineStyleEvent event) {
         IDocument document = getDocument();
         if (document != null) {
             MessageConsolePartitioner partitioner = (MessageConsolePartitioner)document.getDocumentPartitioner();
             if (partitioner != null) {
                 ITypedRegion[] regions = partitioner.computePartitioning(event.lineOffset, event.lineOffset + event.lineText.length());
                 StyleRange[] styles = new StyleRange[regions.length];
                 for (int i = 0; i < regions.length; i++) {
                     MessageConsolePartition partition = (MessageConsolePartition)regions[i];
                     Color color = partition.getStream().getColor();
                     styles[i] = new StyleRange(partition.getOffset(), partition.getLength(), color, null);
                 }
                 event.styles = styles;
             }
         }
     }
 }
